The opportunities and problems pertaining to harvesting and using rainwater is a critically important issue to the community and to the water industry. Nearly 17 percent of Australian households, particularly in rural and remote areas, use rainwater tanks. Rainwater is also becoming a supplementary source of household water in many urban areas. Research into the potential use of rainwater in high-density developments is an important area of inquiry for water utilities around the world as they consider alternative servicing strategies that promote water conservation and environmental sustainability. This paper discusses quality issues associated with the use of untreated rainwater as a source of hot water for household use, and reviews issues pertaining to ongoing maintenance of water quality. The discussion and review are derived from findings of a pilot rainwater quality-monitoring and testing program undertaken in Melbourne, Australia.